This invention relates to a polyester/nylon bicomponent filament that does not come apart along the interfacial junction of the polymers during normal fiber processing or during normal fabric manufacturing processes. This invention also relates to a bicomponent filament that when heated in the form of yarn under low or no tension will shrink and crimp without splitting along the interfacial junction line of the polymers, resulting in a yarn having high bulk, good cover, and spun-like tactile aesthetics.
Bicomponent textile filaments of polyester and nylon are known in the art, and are described in Harcolinski et al., U.S. Pat. No. 3,489,641. According to the aforesaid patent, a yarn that crimps but does not split on heating is obtained by using a particular polyester. The invention of this application is another bicomponent filament having these desirable properties.
It is also known to employ as the polyester component of the bicomponent filament a polyester which is free from antimony, it having been determined that antimony in the polyester reacts with nylon to form a deposit in the spinneret which produces a shorter junction line, and thus a weaker junction line. Such products are claimed in U.S. patent application Ser. No. 168,152, filed July 14, 1980. The present invention uses antimony-free polyester taught to be beneficial by the aforesaid case.
It is also known to make bicomponent filaments using poly[ethylene terephthalate/5-(sodium sulfo) isophthalate] copolyester as the polyester component. Stanley U.S. Pat. No. 4,118,534 teaches such bicomponents. In the bicomponent filament of the present invention the polyester is such a copolyester.
It is also known to make bicomponent filaments in which the one component partially encapsulates the other component. Matsui et al. U.S. Pat. No. 3,607,611 teaches such a bicomponent filament. In the bicomponent filament of the present invention one of the polymeric components is partially encapsulated by the other polymeric component.
It is also known to produce bicomponent filaments in which the interfacial junction between the two polymeric components is at least in part jagged. Kobayashi et al. U.S. Pat. No. 3,781,399 teaches such a bicomponent filament. In the bicomponent filaments of the present invention the interfacial junction between the two polymeric components is at least in part jagged.
Finally, bicomponent filaments having a cross sectional dumbbell shape are known in the art. Ryan et al. U.S. Pat. No. 3,092,892 teaches such bicomponent filaments. The bicomponent filaments of the present invention have a dumbbell cross sectional shape.